关键词： 动力机械   钢结构建筑物   振动位移  

摘要： 随着经济的发展,动力机械设备运用到钢结构的建筑,改善了建筑结构,提高建筑结构的性能。文章通过分析了钢结构建筑的特点和钢结构建筑中的动力机械,深入的探析了钢结构建筑中动力机械设备的设计和动力机械在钢结构建筑物中的应用。

关键词： Nickel oxide  

摘要： The hydrodeoxygenation (HDO) of 1-octanol as a model aliphatic alcohol of bio-oil was investigated in a continuous down-flow fixed-bed reactor over gamma-Al2O3, SiO2, and HZSM-5 supported nickel catalysts in the temperature range of 488-533 K. The supported nickel catalysts were prepared by incipient wetness impregnation method and characterized by BET, XRD, TPR, TPD, H-2 pulse chemisorption, and UV-vis spectroscopy. Characterization of supported nickel (or nickel oxide) catalysts revealed existence of dispersed as well as bulk nickel (or nickel oxide) depending on the extent of nickel loading and the nature of the support. The acidity of gamma-Al2O3 supported nickel catalysts decreased with increasing the nickel loading on gamma-Al2O3. n-Heptane, n-octane, di-n-octyl ether, 1-octanal, isomers of heptene and octene, tetradecane, and hexadecane were identified as products of HDO of 1-octanol. The C-7 hydrocarbons were observed as primary products for catalysts with active metal sites such as gamma-Al2O3 and SiO2 supported nickel catalysts. However, C-8 hydrocarbons were primarily formed over acidic catalysts such as pure HZSM-5 and HZSM-5 supported nickel catalyst. The 1-octanol conversion increased with increasing nickel loading on gamma-Al2O3, and temperature and decreasing pressure and WHSV. The selectivity to products was strongly influenced by temperature, nickel loading on gamma-Al2O3, pressure, and types of carrier gases (nitrogen and hydrogen). The selectivity to C-7 hydrocarbons was favoured over catalysts with increased nickel loading on gamma-Al2O3 at elevated temperature and lower pressure. A comprehensive reaction mechanism of HDO of 1-octanol was delineated based on product distribution under various process conditions over different catalysts.

摘要： 备受社会各界关注的京台高速合肥至蚌埠段大修工程从2014年4月开始大规模施工,预计2014年9月底完成合肥至蚌埠方向的改善任务并开放交通.同时,对蚌埠至合肥方向路面开展封闭施工,计划2015年8月底完成.京台高速合肥至蚌埠段大修工程全长105.38 km,北起蚌埠境内仁和集互通枢纽,南至肥东境内的路口互通枢纽.

关键词： ACTIVATION (Chemistry)   IMIDAZOLES   SULFONATES   ANTINEOPLASTIC agents   METASTASIS   CANCER cells   NEPHROTOXICOLOGY  

摘要： Imidazolium trans-[tetrachloridodimethylsulfoxideimidazoleruthenate(III)], NAMI-A, is a promising antimetastatic prodrug with high specificity for metastatic cancer cells. Limited activity of NAMI-A against primary tumor suggests that its use in combination with other anticancer drug(s) might present a more desirable therapeutic outcome. The mechanism of activation and action of this prodrug is still largely unknown. The biological targets, as well, have not yet been delineated. The kinetics and mechanism of interaction of NAMI-A with 2-mercaptoethane sulfonate, MESNA, a chemoprotectant, have been studied spectrophotometrically under pseudo-first order conditions of excess MESNA. The reaction is characterized by initial reduction of NAMI-A and formation of dimeric MESNA as evidenced by electospray ionization mass spectrometry. A first order dependence on both NAMI-A and MESNA was obtained and a bimolecular rate constant of 0.71 ± 0.06 M[-1] s[-1] was deduced. Activation parameters determined (△S[#] = -178.12 ± 0.28 J K[-1] mol[-1], △H[#] = 20.64 ± 0.082 kJ mol[-1] and △H[#] = 75.89 ± 1.76 kJmol[-1] at 37 ± 0.1 °C and pH 7.4) are indicative of formation of an associative intermediate prior to product formation and subsequent hydrolysis of the reduced complex. Our results suggest that MESNA might be able to activate the prodrug while still protecting against toxicity when given in a regimen involving NAMI-A and chemotherapy drug(s) that induce bladder and kidney toxicities. [ABSTRACT FROM AUTHOR]

关键词： 康明斯   装载机   旗舰产品   发动机   挖掘机械   马力  

摘要： 康明斯在上海bauma展上首次展示了为特定应用市场量身定制的专属动力系列新品——QSF3.8(10-17t挖掘机、4-10t叉车专属动力)、QSB7(20-30t挖掘机专属动力)全电控非公路用三阶段发动机,同台展示的还包括QSF2.8至QSX15非公路用轻、中、重型全系列发动机,排放技术先锋的代表产品Tier 4Final QSL8.9发动机,康明斯大马力的旗舰产品QSK60发动机,以及先进的康明

关键词： 工程机械   液压系统   动力匹配   控制  

摘要： 随着科学技术的快速发展，越来越多的工程机械投入到工程建设当中。其中工程机械液压动力系统的优化匹配控制技术就集合了目前多种理论与技术的一项高级系统技术。本文结合笔者多年的从业经验，阐述了传统的技术设计，详细分析了工程机械液压系统动力匹配的机电一体化控制技术，就控制技术中的设计重点进行探讨，以供同行参考与借鉴。

关键词： Epigenetics   MODIFICATION   EQUIPMENT   Epigenetic Change   machinery   stress tolerance   Histones   abiotic stress  

摘要： Abiotic stress induces several changes in plants at physiological and molecular level. Plants have evolved regulatory mechanisms guided towards establishment of stress tolerance in which epigenetic modifications play a pivotal role. We provide examples of gene expression changes that are brought about by conversion of active chromatin to silent heterochromatin and vice versa. Methylation of CG sites and specific modification of histone tail determine whether a particular locus is transcriptionally active or silent. We present a lucid review of epigenetic machinery and epigenetic alterations involving DNA methylation, histone tail modifications, chromatin remodeling, and RNA directed epigenetic changes.

关键词： 热能   动力机械   能源   环境  

摘要： 热能动力工程是研究能量以热、功形式传递和转化的过程和应用，以及在这个过程中涉及到的装置的一门学科。因此，我们可以从一些常用的机械去了解它。

关键词： 变结构   行驶机构   运动学   动力学   ADAMS  

摘要： 特定环境，特别是核环境下的工程装备，都要求其控制系统简单，工作可靠性高。因此，不需要通过测控，仅仅依靠装备的结构变化和调整就能适应环境变化的自适应机械结构已成为特种工程装备的研究方向和热点之一。行走机构是工程装备实现智能化、自适应外部地面路况变化的重要机构，对其研究也越来越得到专家学者的重视。 本文提出一种拥有多自由度变结构的轮腿式行走机构，重点研究机构的构型及其结构的参数模型，分析了其运动学和动力学性能，通过仿真对机构的各项性能进行了理论分析。 本文主要完成工作包括: 1）分析人体手臂的结构和功能，在对手臂骨骼结构简化和改进基础上得到特种工程机械行走机构的支腿结构。 2）对具有变结构特性的行走机构进行运动学正分析和运动学逆分析，得到：行驶机构支腿在行驶过程中随时间变化的位置坐标；支腿的速度和加速度的显示表达式；支腿的工作空间；在给定支腿位置和姿态时支腿各关节的转动角度。 3）初步确定了行走机构的尺寸参数；使用三维绘图分析软件Pro/E建立了行走机构的三维模型；分析了行走机构的运动模式；把提出的行走机构与挖掘机上车相结合，组成轮腿式挖掘机，并对其越障能力进行了分析。 4）把挖掘机三维模型导入机械系统动态仿真软件ADAMS中，对其进行了动力学仿真分析，验证了行走机构的变结构特性，得到了挖掘机在行驶过程中行走机构的受力情况；对挖掘机施加一定工作载荷，得到挖掘机作业时行走机构的受力情况。 研究分析结果表明，行驶机构具有多姿态特性和较强的路面适应能力及越障能力。如果在行走机构上配备计算机控制系统和足够的传感器，便可实现智能化的功能。

关键词： LAVENDERS   DRAG (Aerodynamics)   HARVESTING   TENSILE strength   PLANT stems   REYNOLDS number   AGRONOMY  

摘要： A laboratory study evaluated the physical and aerodynamic properties of lavender cultivars in relation to the design of an improved lavender harvester that allows removal of flowers from the stem using the stripping method. The identification of the flower head adhesion, stem breakage, and aerodynamic drag forces were conducted using an Instron 1122 instrument. Measurements on five lavender cultivars at harvest moisture content showed that the overall mean flower detachment force from the stem was 11.2N, the mean stem tensile strength was 36.7N, and the calculated mean ultimate tensile stress of the stem was 17.3MPa. The aerodynamic measurements showed that the drag force is related with the flower surface area. Increasing the surface area of the flower head by 93% of the "Hidcote" cultivar produced an increase in drag force of between 24.8% and 50.6% for airflow rates of 24 and 65ms(-1), respectively. The terminal velocities of the flower heads of the cultivar ranged between 4.5 and 5.9ms(-1), which results in a mean drag coefficient of 0.44. The values of drag coefficients were compatible with well-established values for the appropriate Reynolds numbers.